Magnesium base alloy



used for castings but Patented July 2, 1935 MAGNESIUM BASE ALLOY Robert T. Wood,

mesne assignment Cleveland, Ohio, assignor, by

s, to Magnesium Development Corporation, a corporation of Delaware No Drawing. Application May 18, 1934, Serial No. 726,317

This invention relates to magnesium base alloys 3 Claims.

Magnesium base alloys been experienced in type. Magnesium a low ductility at hot workin consequently develop internal as well as external cracks.

have been extensively considerable difficulty has hot working alloys of this base alloys generally possess g temperatures and ruptures very easily Such breaks in the continuity of the alloy structure are not healed by subsequent working with worked article must be the result that the discarded. Even the most careful heating and handling of the alloy in hot working operations fails to remedy this condition. It is moreover often desirable to use a wrought article for a given application because of the greater uniformity of structure and higher mechanical properties that are pared to similar properties of a cast attainable as comproduct. It

has been particularly diflicult to hot form magnesium base alloys into intricate shapes which has necessitated the substitution of other materials at the sacrifice of saving in weight.

It is an object of my invention to provide magnesium base alloys that can without developing internal in the structure.

be readily hot worked or external breaks Another object is to produce an alloy that is sufliciently plastic at hot working temperatures to permit successful formation of intricate shapes on a commercial scale.

My invention is predicated that a magnesium base alloy about 1.0 to 15 per cent of tin manganese and 0.1 to 1.0

per cent of silicon,

upon the discovery composed of from 0.1 to 3 per cent of has the aforementioned properties. While the favorable hot working quality of over the entire range of the alloy is manifest composition indicated,

1 have found that in general the most satisfactory combination of working properties and strength is present in alloys containing from about 4 to 10 per cent of tin, 0.5 to 1.5 per cent of manganese and 0.2 to 1 per cent of silicon.

A preferred alloy coming within the last mentioned range is one containing about 6 per cent of tin, 1 per cent of manganese and 0.5 per cent of silicon. This alloy forges very well and is adapted to the making of wrought shapes which have hitherto been very difficult to form. In the forged condition the alloy has a tensile strength of about 34,000 lbs. per sq. in., a yield strength of about 21,000 lbs. per sq. in., and an elongation of about 4 per cent in two inches.

The hot working operations on magnesium base alloys have usually been conducted between the temperatures of about 500 and 800 F. but with my improved-alloy it is possible to heat the work up to as high as 950 F. without danger of hot shortness. The higher temperature aids in giving greater plasticity to the alloy; as well as the nature of the alloying constituents.

The alloys herein disclosed respond to the usual thermal treatments employed in the art to'improve the mechanical properties of magnesium base alloys.

The term magnesium base alloy as used hereinabove and in the appended claims refers to those alloys containing 50 per cent or more of magnesium.

I claim:

1. A magnesium base alloy composed of from about 1 to 15 per cent of tin, 0.1 to 3.0 per cent of manganese, and 0.1 to 1.0 per cent of silicon, the balance magnesium.

,2. A magnesium base alloy composed of from about 4 to 10 per cent of tin, 0.5 to 1.5 per cent of manganese and 0.2 to 1 per cent of silicon, the balance magnesium.

3. A magnesium base alloy consisting of about 6 per cent of tin, 1 per cent of manganese and 0.5 per cent of silicon, the balance magnesium.

ROBERT T. WOOD. 

